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  • [♪ INTRO]

  • I don't know what you've been doing with your first full week of 2019,

  • but the space community has been knocking it out of the park.

  • It's been 11 days, and this year is already a great one for space exploration.

  • First, as we were all celebrating the start of the new year, NASA's New Horizons was

  • zipping past the farthest object ever visited by a spacecraft.

  • Then, only days later, China accomplished something just as remarkable: For the first

  • time ever, they safely put a lander on the far side of the Moon!

  • Meanwhile, I had a hard time getting out of bed, multiple days in a row.

  • It'll be a while before we have all of the data we're gonna get from these two missions,

  • but they're already proving that our solar system

  • is way more fascinating than it has any right to be.

  • The object New Horizons flew by is named 2014 MU69, but the mission team sometimes calls

  • it Ultima Thule, after the ancient Latin term for distant, unexplored lands.

  • And it is definitely distant.

  • MU69 is what planetary scientists call a Kuiper belt object, or KBO,

  • meaning it orbits in a region of space beyond Neptune.

  • The most famous Kuiper belt object is the dwarf planet Pluto,

  • which also happened to be New Horizons' first target.

  • And while it's turned out to be an amazing place, tiny MU69, which is only around 30

  • kilometers long, is probably more representative of what most KBOs are like.

  • So far, New Horizons has only sent back the first few pictures it snapped during the flyby,

  • but they've already revealed that this place is a weird, weird world.

  • Like, it looks like maybe a peanut, or a little snowman.

  • Between that and Pluto's heart, New Horizons studies all the coolest looking places!

  • Astronomers call objects like MU69 contact binaries.

  • Binary because there are two objects, and contact because they're touching.

  • The two parts probably formed out of the same cloud of material and then drifted together

  • really slowly because of their shared gravitational pull.

  • Today, they spin as one object, rotating about once every fifteen hours.

  • Scientists couldn't figure that out before because MU69 keeps the same

  • pole pointing towards Earth all the time.

  • But now that we know what this object looks like, we have even more questions,

  • like what is going on with all the color variation.

  • Both parts of MU69 have the same reddish color, which is similar to the north pole of Pluto's

  • moon Charon and seems to be pretty common for KBOs.

  • But theneckregion appears to be much brighter, as do a few spots along the surface.

  • Of course, “brightis relative here.

  • Overall, MU69 is about the brightness of nice, dark potting soil.

  • Even the lightest spots have just 13% reflectivity.

  • Regardless, mission scientists say that those bright spots seem to correspond with surface

  • depressions, but we will have to wait for better images to be sure.

  • Unfortunately, it will take a long time to get that data.

  • Like you might guess, there's not exactly a 4G network at the edge of the solar system.

  • Download speeds are really, really slow, so it will take about twenty months to retrieve

  • data that was collected in just a few hours. It reminds me of the 90's.

  • Mission controllers expect the very best pictures to arrive in February, but images are just

  • one piece of the treasure-trove New Horizons has gathered.

  • It took plenty of other measurements as well,

  • so, stay tuned for much more about the Kuiper belt this year.

  • Speaking of much more news, last week we told you 2019 would be a groundbreaking year for

  • exploring the Moon, and it already is!

  • On January 3rd, local time, China's Chang'e-4 lander touched down on the far side of the Moon.

  • Then, just hours later, it deployed its Yutu-2 rover.

  • This mission is really exciting for a few reasons, but mainly,

  • because the Moon's far side has long puzzled planetary scientists.

  • It's covered by more craters and fewer lava flows than the parts of the Moon visible from Earth.

  • And because all of NASA's Apollo missions landed on the near side,

  • we know dramatically less about what might be going on.

  • Chang'e-4 has landed in the massive South Pole-Aitken basin,

  • one of the solar system's largest impact craters.

  • Seriously, this crater is half the size of the continental United States.

  • The impact that formed it may have been so violent that it excavated some of the Moon's

  • inner material, called the mantle.

  • So if Chang'e-4 or its rover can locate any mantle material, it would help scientists

  • understand early lunar history, and we wouldn't even have to dig for it.

  • What's also cool about this mission is the engineering that was required to pull it off.

  • Landing on the far side of the Moon is especially difficult because it's

  • always out of view from the Earth.

  • That means it's impossible to directly communicate with anything that lands there,

  • a situation that's basically unique in the solar system.

  • Even NASA's Mars rovers can communicate directly with Earth in an emergency.

  • To stay in touch with the lander, China had to place the first-ever communication satellite

  • in Earth-Moon L2, a point of gravitational equilibrium just beyond the Moon.

  • It launched last May, and can now relay signals between Chang'e-4 and Earth.

  • And while it did require some extra engineering, the trade-off was worth it.

  • As a bonus, Chang'e-4 can also make use of this silence of the far side of the moon

  • to conduct radio experiments that would be impossible anywhere else in Earth orbit.

  • So, from the mission design to its results, this is a big moment for the Chinese space program.

  • With the original Yutu rover in 2013, China had already joined the U.S. and Russia as

  • the only nations to have operated rovers on another world.

  • Now, for the first time, they're doing something no other country has done.

  • And that's really great news for science.

  • Thanks for watching this episode of SciShow Space News!

  • From new missions to groundbreaking new papers, we're here covering the latest news from

  • around the universe every Friday.

  • If you want to keep learning with us, you can go to youtube.com/scishowspace and subscribe.

  • [♪ OUTRO]

[♪ INTRO]

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我們首次登陸月球遠端!| 科學秀新聞 (We Just Landed on the Far Side of the Moon for the First Time! | SciShow News)

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    林宜悉 發佈於 2021 年 01 月 14 日
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